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[PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code

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If we send zero-length data to stm32_qspi_tx_poll() on older
compiler versions such as gcc-4.6, we get warned that the
return code is uninitialized:

drivers/mtd/spi-nor/stm32-quadspi.c:248:2: error: ‘ret’ may be used uninitialized in this function [-Werror=uninitialized]

On newer compiler versions, the return code is always zero
in this case, as the local variable gets optimized away and
is assumed to be zero after the loop completes without error.

This changes the function to instead return -EINVAL if it
ever gets called with a zero length buffer.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82203
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/mtd/spi-nor/stm32-quadspi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/stm32-quadspi.c b/drivers/mtd/spi-nor/stm32-quadspi.c
index 86c0931543c5..711cfe7aa4bf 100644
--- a/drivers/mtd/spi-nor/stm32-quadspi.c
+++ b/drivers/mtd/spi-nor/stm32-quadspi.c
@@ -227,7 +227,7 @@ static int stm32_qspi_tx_poll(struct stm32_qspi *qspi,
 	void (*tx_fifo)(u8 *, void __iomem *);
 	u32 len = cmd->len, sr;
 	u8 *buf = cmd->buf;
-	int ret;
+	int ret = -EINVAL;
 
 	if (cmd->qspimode == CCR_FMODE_INDW)
 		tx_fifo = stm32_qspi_write_fifo;
-- 
2.9.0

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[PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code Arnd Bergmann <arnd@arndb.de> - 2017-09-14 13:10 +0200
  Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return  code Ludovic BARRE <ludovic.barre@st.com> - 2017-09-14 14:50 +0200
  Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code Geert Uytterhoeven <geert@linux-m68k.org> - 2017-09-14 15:40 +0200
    Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return  code Ludovic BARRE <ludovic.barre@st.com> - 2017-09-14 17:20 +0200
      Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code Geert Uytterhoeven <geert@linux-m68k.org> - 2017-09-14 17:30 +0200
        Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return  code Ludovic BARRE <ludovic.barre@st.com> - 2017-09-14 19:00 +0200
          Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return code Arnd Bergmann <arnd@arndb.de> - 2017-09-14 23:40 +0200
            Re: [PATCH] mtd: spi-nor: stm32-quadspi: avoid unintialized return  code Ludovic BARRE <ludovic.barre@st.com> - 2017-09-15 10:10 +0200

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